The present invention relates to a method and to equipment for use in rescue service operations generally, for making at least one hole in structures, such as buildings of various kinds, cisterns, tanks and containers designed for various purposes, vehicles, trains and ships, etcetera, in case of accidents or other emergency situations to allow evacuation of gases and liquids and to rescue lives and property, etcetera, and for making holes in roofs, walls, etcetera in fighting fires in structures of the kind outlined above, for the purpose of venting combustion gases and particularly for fire-extinguishing purposes.
Briefly speaking, combustion-gas venting involves controlling, in the case of fires, the extension and development of the fire by affecting the gases that generate during the fire. In practical terms this means cooling the combustion gases and discharging them into the ambient atmosphere via holes that are being made for that purpose, or via hatches, windows, lanterns, sky-lights and the like. The purpose of combustion-gas venting is, primarily, to allow safe evacuation of humans and livestock and to improve the possibilities of saving lives and property, to offer the rescue personnel increased extinguishing and penetration possibilities and to contain the fire and reduce excess pressures and temperatures, and so on.
Hole-making for fire venting and fire fighting purposes is at present effected essentially by means of such hand-held implements as axes, crowbars and break-up iron bars, angular grinding and/or cutting machines, etcetera. More recent equipment and methods use explosive frames, whereby holes are made with the aid of explosions. Explosive frames for this purpose are, however, comparatively expensive and contain explosives, with ensuing strict requirements on above all storage and handling conditions.
Irrespective of whether hand-operated implements and/or explosive frames or the like are used, working with this kind of equipment is very dangerous, both because the rescue personnel need to walk on for instance large flat or more or less steeply inclined roofs on the building on fire in order to make the holes, and because the very handling of the implements and the explosive frames is hazardous, involving risks that the individuals be thrown or clamped. and, when explosive frames are used, risks of premature detonation.
The main object of the present invention is to eliminate as far as possible the above referred-to hazards and disadvantages and to suggest a novel, efficient and safe method and equipment for use in rescue service operations for making holes in structures of the kind outlined in the introduction hereto.
With respect to the method, this main object is achieved in that the hole or holes are produced by means of cutting, using a pressurized liquid which while cutting is sprayed into the structure in question in the shape of a jet for allowing evacuation of gases and liquids and saving of lives and property.
With respect to the equipment, this main object is achieved by the provision of a source of pressurized medium having an outlet for a pressurised liquid, of a conduit, and of a nozzle having an inlet and an outlet, said conduit being connected at one of its ends to the outlet of the source of pressurised medium and at its opposite end to the inlet of the nozzle for supply of pressurised fluid from the source of pressurised medium to the outlet of the nozzle, from which the liquid in the form of a jet is caused to be discharged and to be directed towards the structure in question, in order to cut through said structure to form said number of holes, and in connection with said cut-through to be sprayed into the structure in the form of a jet to evacuate gases and liquid and to rescue lives and property.
A further object of the method is to suggest a method and equipment as defined above for making at least one hole in the roof, walls, etcetera for fighting fires in structures of the kind outlined in the afore-going for venting combustion gases and to extinguish fires.
With respect to the method, this further object is achieved in that the hole or holes are produced by means of cutting, using a pressurised liquid which while cutting is sprayed into the space on fire in the shape of a jet which rapidly evaporates and in doing so contributes to extinguishing the fire, the combustion gases being vented through the cut hole or holes.
The equipment for achieving this further object includes a source of pressurised medium having an outlet for a pressurised liquid, a conduit, and a nozzle having an inlet and outlet, said conduit being connected at one of its ends to the outlet of the source of pressurised medium and at its opposite end to the inlet of the nozzle, for supply of pressurised fluid from the source of pressurised medium to the outlet of the nozzle, from which the liquid in the form of a jet is caused to be discharged and to be directed towards the roof, the wall, etcetera, in order to cut through said roof, wall, etcetera to form said at least one hole, and in connection with said cut-through to be sprayed into the structure in question on fire in order to assist in extinguishing the fire.
In accordance with the teachings of the invention a very rapid, efficient and above all safe method and equipment are provided for use in rescue service operations for making holes in structures of the kind defined in the introduction, particularly for making holes in structures on fire of the kind defined above.
Experiments show that conventionally structured roof comprising e.g. external roofing sheets, insulation and internal roofing sheets having a total thickness of 20-30 cm was cut through in only a few seconds, and in the case of the most difficult experiment, the cutting speed amounted to 1 m/min. The considerable safety offered by the method and the equipment is related to the fact that contrary to the case when cutting tools, explosive frames and similar equipment are used, the inventive method and equipment do not in themselves generate heat and/or sparks.